topic Re: Cropping a surface using a polyline in Civil 3D Forum

Cropping a surface using a polyline

mabrman — Thu, 22 Aug 2024 09:51:03 GMT

Howdy,

I'm working with a large surface (100,000+ points) and need to generate multiple surfaces representing small areas of this surface. My first thought was to create a surface that will represent the first clipped area, and paste in the large surface into it, then add boundary. When exporting this surface, it still contains ALL 100,000+ points from the large surface, making the resulting surface slow to work with, and large LandXML size when exporting, even though the clipped area represents 1-3% of the size of the big surface.

I've tried using CREATECROPSURFACE command (horrible experience using this command), but it's only able to clop using a rectangle. (Is there any way to use a polyline for this crop?)

How can I create a bound surface while removing all geometry including points outside of the polyline extents?

As a demo consider 5x5 point grid starting at 0,0 coordinates.

Create a surface using all 25 of these points. Then create a boundary as seen in yellow in the image below.

When showing points in the surface style (red below), it shows what I'd want the final surface to contain, however when exporting LandXML I still see all points outside of the boundary still present when reading the LandXML file as plaintext.

I suppose for this demo the CREATECROPSURFACE command would work, since it's a perfect rectangle, however that's not the case.

I've developed some blender add-ons to help me do these tasks very efficiently, but when asked by my colleagues how to achieve this in Civil 3D, I'm at a loss.

Any ideas appreciated.

Matt

Re: Cropping a surface using a polyline

neilyj666 — Thu, 22 Aug 2024 10:58:02 GMT

Polygon works fine for me

Re: Cropping a surface using a polyline

mabrman — Thu, 22 Aug 2024 11:15:32 GMT

I feel like a idiot, while I hate that you have to have the drawing saved to use this command, and then if you try to insert the surface into current drawing it doesn't work (didn't work for me), there wasn't any indication that I can use a object or a polyline until I turned on DYNAMIC INPUT (where console line follows your cursor).

Attached video showing how console goes missing during command execution unless dynamic input is on:

(view in My Videos)

Re: Cropping a surface using a polyline

neilyj666 — Thu, 22 Aug 2024 11:31:37 GMT

I get the same as you when using the command line version. I have dynamic input off BUT I use the command from the ribbon rather than the command line and this gives the options. This seems like a bug - have you raised a support ticket?

Re: Cropping a surface using a polyline

mabrman — Thu, 22 Aug 2024 11:35:33 GMT

I haven't raised a bug. Feels like a bug, but I'm thinking they see it as a feature of the UI system Civil 3D uses. Raising bugs in the past made me feel stupid for not knowing how to use the tools that "have been working for decades"... Feel free to bring it to their attention if you'd like.

Thank you for showing that polyline can be used. Appreciate the help

Re: Cropping a surface using a polyline

neilyj666 — Thu, 22 Aug 2024 11:41:15 GMT

I don't use the command line for most things and it works fine from the ribbon so the likely reply would be "not a bug but a user experience feature"

Re: Cropping a surface using a polyline

teerawat.pSCHYQ — Fri, 23 Aug 2024 08:50:47 GMT

you said that you working with a large surface (100,000+ points), I guess you created large surface from that input and then using CREATCROPSURFACE command, It is horrible for you. I suggest that you crated surface in small area first what you would like to work, but before definition input, you can using boundary type "DATA Clip" first and then definition data into your surface, then you will get small surface size that you can work smoothly.

Re: Cropping a surface using a polyline

mabrman — Fri, 23 Aug 2024 08:59:19 GMT

Thank you for the suggestion. I believe that would work during the initial surface creation, however the surface was provided to me by a contractor, and so my starting point is the LandXML. Previously I made a rough guess about the number of points - it's 74,000, but still a headache to work with in Civil 3D.

The CREATECROPSURFACE did solve the trick when running it from the toolbar instead of the command line though. 🙂

Re: Cropping a surface using a polyline

teerawat.pSCHYQ — Mon, 26 Aug 2024 03:10:12 GMT

Ok, as you said that your surface are created by contractor, so then you can try like this, after import that LandXML file then you can make it to data shortcut for the large area, and then you can using that createcropsurface command to create a new file that maybe call in working area what you need (my example just create a new file call "Large file_after create crop surface" and then you can make this file to data shortcut that easy to recreate surface and add to your file. as you see i just simple try this way, It will reduce your file size more than 75% like this below.